Effect of positive-end-expiratory-pressure on right ventricular output in lambs with hyaline membrane disease.

Right and left ventricular outputs, pulmonary and systemic blood flows, and blood flows in both directions through the ductus arteriosus were measured before and during positive-end-expiratory-pressure in 5 premature lambs with induced hyaline membrane disease. During positive-end-expiratory-pressure, right ventricular output increased in all lambs without any significant change in left ventricular output or pulmonary vascular resistance. Left-to-right ductus flow decreased in lambs which initially had large left-to-right ductus shunts.

Internal laryngocele and saccular cysts in children.

Two children, one with an internal laryngocele and the other with a lateral saccular cyst are described. The anatomy, classification, and history of these unusual lesions are described. The diagnosis and management are discussed.

Evaluation of tonsils and adenoids in Sleep Apnea syndrome.

Peripheral Sleep Apnea syndrome has been associated with enlarged tonsils and adenoids as well as other abnormalities which may cause upper airway obstruction in children. A multidisciplinary approach is used at the Step Disorder Center of Cincinnati General Hospital to evaluate the role of tonsils and adenoids in sleep apnea. Polysomnographic techniques combined with cine sleep studies of the upper airway document the degree, site and type of obstruction.

Impedance cardiographic assessment of symptomatic patent ductus arteriosus.

A modified impedence cardiographic technique was developed using a tetrapolar apnea monitor and minicomputer system. Evaluation of this technique in premature infants with and without symptomatic patent ductus arteriosus indicates that the magnitude of the cardiac-related deflection in the impedance signal is useful in the assessment of ductus shunting. Since the infant under study is involved only by the attachment of two double electrodes to the thorax, continuous assessment of ductur shunting is possible without disturbing routine care.

Altered copper metabolism in cultured cells from human Menkes' syndrome and mottled mouse mutants.

Cultured cells of a variety of different types from human Menkes' syndrome patients and brindled mouse mutants exhibit similarly altered responses to changes in extracellular copper concentration. This suggests that the mutations in the mouse and human are very similar and that mutant gene expression is occurring in many different tissues. Intracellular copper levels are markedly elevated in mutant cells in normal medium and in medium containing a hundred-fold higher copper.

Tracheoplasty for tracheal stenosis in the pediatric burned patient.

Until recently, the only therapy available for a tracheal stricture has been repeated dilations of the stenotic area or resection and anastomosis. Upper-airway burns in the pediatric patient have occasionally resulted in tracheal stenosis. Two children with a long tracheal stenosis secondary to inhalation injury have been successfully treated surgically.

Observations indicating the nature of the mutation in phenylketonuria.

Rabbit antiserum was prepared against purified normal human liver phenylalanine hydroxylase. This was used to test for cross-reacting material in crude extracts of livers from patients with classical phenylketonuria (PKU); the samples from patients were two livers obtained at autopsy and a needle biopsy core. None of these enzymically inactive livers contained detectable cross-reacting material capable of neutralizing antibody activity in double immunodiffusion and/or enzyme inhibition experiments.

Electron microscopic analysis of RNA transcription in preimplantation rabbit embryos.

We have examined directly RNA synthesis in several stages of preimplantation rabbit embryos by electron microscopic analysis of chromatin spreads. DNA/chromatin packing ratios were determined for non-transcribing regions (2.0) and for regions active in RNA synthesis (1.

Dihydropteridine reductase deficiency diagnosis by assays on peripheral blood-cells.

Human peripheral lymphocytes, granulocytes, and platelets contain the enzyme dihydropteridine reductase. A simple procedure and assay for diagnosing dihydropteridine reductase on peripheral blood is described. In twelve controls the level of enzyme activity in a lymphocyte-platelet preparation was 29.

Retropharyngeal abscesses in children revisited.

Retropharyngeal abscess appears in infancy and early childhood. Because of the advances in antibiotic therapy, the frequency of this disease has decreased considerably. If overlooked, however, the sequelae of retropharyngeal abscess can be disastrous.

Congenital abnormalities induced by heterologous antisera directed against rat kidney glycoproteins isolated by concanavalin A affinity chromatography.

It has been well established that heterologous antisera against whole rat kidney homogenate when injected into pregnant rats during the embryonic organogenetic period may induce abnormal embryonic development. Attempts were made to isolate the active components from soluble rat kidney extract by ammonium sulfate precipitation, anion-exchange chromatography, and concanavalin A-Sepharose 4B affinity chromatography. The glycoproteins isolated were capable of stimulating the production of potent rabbit antisera.

Genetics of the mammalian phenylalanine hydroxylase system. II. Immunological and two-dimensional gel electrophoretic studies of phenylalanine hydroxylase in cultured normal and mutant rat hepatoma cells.

We have examined 11 previously described cultured rat hepatoma mutants with absent or reduced phenylalanine hydroxylase activity (Choo and Cotton, 1977). Immunological and electrophoretic methods failed to detect any structurally altered protein in these mutants. In nine independently isolated revertants from four different mutants, wild-type protein was regained (or accentuated).

Abnormal deoxyribose metabolites in the urine of a child with a possible new inborn error of metabolism.

The urinary extract of a child investigated because of strabismus was found to contain large amounts of a compound which was identified using gas chromatography/mass spectrometry as 2-deoxyerythropentono-1,4-lactone. This lactone has not been observed previously in urinary extracts. When ion-exchange chromatography was used to isolate the organic acids from urine, the major peaks obtained by gas chromatography were shown to be 2-deoxyerythropentonic acid, 2-deoxyerythropentono-1,5-lactone and 2-deoxyerythropentono-1,4,lactone.

Malignant hyperphenylalaninemia--clinical features, biochemical findings, and experience with administration of biopterins.

Four cases of malignant hyperphenylalaninemia (MHPA) are described. Pretreatment serum phenylalanine levels were 1.5, 3.

Genetics of the mammalian phenylalanine hydroxylase system. Studies of human liver phenylalanine hydroxylase subunit structure and of mutations in phenylketonuria.

Phenylalanine hydroxylase was purified from crude extracts of human livers which show enzyme activity by usine two different methods: (a) affinity chromatography and (b) immunoprecipitation with an antiserum against highly purified monkey liver phenylalanine hydroxylase. Purified human liver phenylalanine hydroxylase has an estimated mol. wt.

Human dihydropteridine reductase: a method for the measurement of activity in cultured cells, and its application to malignant hyperphenylalaninemia.

1. The kinetic, assay and culture variables involved in the determination of dihydropteridine reductase activity in human cultured cells have been investigated, and a modified assay is described which allows for accurate determination of activity. Unlike previously used assays, this assay utilizes saturating concentrations of substrates and its increased sensitivity allows for excellent replication on a smaller number of cells than was previously required.